350352015eng571579conferenceobjectAmer inst physicsMelville, NY, USALaser Institute of America (LIA)0------Full penetration laser beam welding of thick duplex steel plates with electromagnetic weld pool supportFull penetration high power bead-on-plate laser beam welding tests of up to 20 mm thick 2205 duplex steel plates were performed in PA position. A contactless inductive electromagnetic (EM) weld pool support system was used to prevent gravity drop-out of the melt. Welding experiments with 15 mm thick plates were carried out using IPG fiber laser YLR 20000 and Yb:YAG thin disk laser TruDisk 16002. The laser power needed to achieve a full penetration was found to be 10.9 and 8.56kW for welding velocity of 1.0 and 0.5 m min(-1), respectively. Reference welds without weld pool support demonstrate excessive root sag. The optimal value of the alternating current (AC) power needed to completely compensate the sagging on the root side was found to be approximate to 1.6 kW for both values of the welding velocity. The same EM weld pool support system was used in welding tests with 20 mm thick plates. The laser beam power (TRUMPF Yb:YAG thin disk laser TruDisk 16002) needed to reach a full penetration for 0.5 m min(-1) was found to be 13.9 kW. Full penetration welding without EM weld pool support is not possible-the surface tension cannot stop the gravity drop-out of the melt. The AC power needed to completely compensate the gravity was found to be 2 kW. (C) 2016 Laser Institute of AmericaICALEO 2015 - 34th International congress on applications of lasers & electro-optics (Proceedings)38187978-1-940168-05-0ICALEO 2015 - 34th International congress on applications of lasers & electro-opticsAtlanta, GA, USA2015-10-182015-10-22Vjaceslav AvilovAndré FritzscheMarcel BachmannAndrey GumenyukMichael RethmeierenguncontrolledElectromagnetic weld pool supportenguncontrolledLaser beam weldingenguncontrolledDuplex stainless steelIngenieurwissenschaften und zugeordnete Tätigkeiten9 Komponentensicherheit9.3 Schweißtechnische FertigungsverfahrenVerlagsliteraturVolltext-PDF im Netzwerk der BAM verfügbar ("Closed Access")350362015eng650659conferenceobjectLaser Institute of America (LIA)0------Finite element modelling of an AC electromagnetic weld pool support in full penetration laser beam welding of thick duplex stainless steel platesAn electromagnetic weld pool support system for 20 mm thick duplex stainless steel AISI 2205 was investigated numerically and compared to experiments. In our former publications, it was shown how an AC magnetic field below the process zone directed perpendicular to the welding direction can induce vertically directed Lorentz forces. These can counteract the gravitational forces and allow for a suppression of material drop-out for austenitic stainless steels and aluminum alloys. In this investigation, we additionally adopted a steady-state complex magnetic permeability model for the consideration of the magnetic hysteresis behavior due to the ferritic characteristics of the material. The model was calibrated against the Jiles-Atherton model. The material model was also successfully tested against an experimental configuration before welding with a 30 mm diameter cylinder of austenitic stainless steel surrounded by duplex stainless steel. Thereby, the effects of the Curie temperature on the magnetic characteristics in the vicinity of the later welding zone were simulated. The welding process was modelled with a 3D turbulent steady-state model including heat transfer and fluid dynamics as well as the electromagnetic field equations. Main physical effects, the thermo-capillary (Marangoni) convection at the weld pool boundaries, the natural convection due to gravity as well as latent heat of solid–liquid phase transitions at the phase boundaries were accounted for in the model. The feedback of the electromagnetic forces on the weld pool was described in terms of the electromagneticinduced pressure. The FE software COMSOL Multiphysics 4.2 was used in this investigation. It is shown that the gravity drop-out associated with the welding of 20 mm thick duplex stainless steel plates due to the hydrostatic pressure can be prevented by the application of AC magnetic fields between around 70 mT and 90 mT. The corresponding oscillation frequencies were between 1 kHz and 10 kHz and the electromagnetic AC powers were between 1 kW and 2.3 kW. In the experiments, values of the electromagnetic AC power between 1.6 kW and 2.4 kW at oscillation frequencies between 1.2 kHz and 2.5 kHz were found to be optimal to avoid melt sagging or drop-out of melt in single pass fullpenetration laser beam welding of 15 mm and 20 mm thick AISI 2205.ICALEO 2015 - 34th International congress on applications of lasers & electro-optics (Proceedings)38188978-1-940168-05-0ICALEO 2015 - 34th International congress on applications of lasers & electro-opticsAtlanta, GA, USA2015-10-182015-10-22Marcel BachmannR. KunzeVjaceslav AvilovMichael RethmeierenguncontrolledElectromagnetic weld pool supportenguncontrolledLaser beam weldingenguncontrolledFE simulationenguncontrolledDuplex stainless steelIngenieurwissenschaften und zugeordnete Tätigkeiten9 Komponentensicherheit9.3 Schweißtechnische FertigungsverfahrenMaterialMaterialien und StoffeVerlagsliteraturVolltext-PDF im Netzwerk der BAM verfügbar ("Closed Access")353672016eng100010-1100010-81706conferenceobjectAIP Publishing1------Laser Based Spot Weld CharacterizationSpot welding is one of the most important joining technologies, especially in the automotive industry. Hitherto,the quality of spot welded joints is tested mainly by random destructive tests. A nondestructive testing technique offers the benefit of cost reduction of the testing procedure and optimization of the fabrication process, because every joint could be examined. This would lead to a reduced number of spot welded joints, as redundancies could be avoided. In the procedure described here, the spot welded joint between two zinc-coated steel sheets (HX340LAD+Z100MB or HC340LA+ZE 50/50) is heated optically on one side. Laser radiation and flash light are used as heat sources. The melted zone, the so called “weld nugget” provides the mechanical stability of the connection, but also constitutes a thermal bridge between the sheets. Due to the better thermal contact, the spot welded joint reveals a thermal behavior different from the surrounding material, where the heat transfer between the two sheets is much lower. The difference in the transient thermal behavior is measured with time resolved thermography. Hence, the size of the thermal contact between the two sheets is determined, which is directly correlated to the size of the weld nugget, indicating the quality of the spot weld. The method performs well in transmission with laser radiation and flash light. With laser radiation, it works even in reflection geometry, thus offering the possibility of testing with just one-sided accessibility. By using heating with collimated laser radiation, not only contactfree, but also remote testing is feasible. A further convenience compared to similar thermographic approaches is the applicability on bare steel sheets without any optical coating for emissivity correction. For this purpose, a proper way of emissivity correction was established.AIP Conference Proceedings978-0-7354-1353-510.1063/1.4940570http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=Alerting&SrcApp=Alerting&DestApp=WOS&DestLinkType=FullRecord;UT=WOS:00037190780012442ND ANNUAL REVIEW OF PROGRESS IN QUANTITATIVE NONDESTRUCTIVE EVALUATION: Incorporating the 6th European-American Workshop on Reliability of NDEMinneapolis, Minnesota, USA26.07.201531.07.201528.04.2016Florian JonietzPhilipp MyrachMichael RethmeierH. SuwalaMathias ZieglerenguncontrolledLaserIngenieurwissenschaften und zugeordnete Tätigkeiten8 Zerstörungsfreie Prüfung8.7 Thermografische Verfahren9 Komponentensicherheit9.3 Schweißtechnische FertigungsverfahrenMaterialMaterialien und StoffeVerlagsliteraturVolltext-PDF im Netzwerk der BAM verfügbar ("Closed Access")353742016eng12713240conferenceobjectElsevier B.V.1------Sustainable welding process selection based on weight space partitionsSelecting a welding process for a given application is crucial with respect to the sustainability of part manufacturing. Unfortunately, since welding processes are evaluated by a number of criteria, preferences for one or the other process can be contradictory. However, the prevalent procedure of weight assignment for each criterion is subjective and does not provide information about the entire solution space. From the perspective of a decision maker it is important to be able to assess the entire set of possible weightings and answer the question which welding process is optimal for which set of weights. This issue is investigated by means of a weight space partitioning approach. Two welding processes are considered with respect to three criteria that reflect their economic and environmental performance. In order to find the most sustainable welding process the underlying weight space partition is evaluated.Procedia CIRP10.1016/j.procir.2016.01.0772212-8271urn:nbn:de:kobv:b43-353740http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=Alerting&SrcApp=Alerting&DestApp=WOS&DestLinkType=FullRecord;UT=WOS:00037924320002313th Global Conference on Sustainable Manufacturing – Decoupling Growth from Resource UseBình Dương New City, Vietnam16.09.201518.09.201505.08.2016Creative Commons - Namensnennung-Nicht kommerziell-Keine BearbeitungG. SproesserS. SchenkerAndreas PittnerR. BorndörferMichael RethmeierY.-J. ChangM. FinkbeinerenguncontrolledWelding costsenguncontrolledMulti-criteria decision supportenguncontrolledLCAenguncontrolledWelding process selectionenguncontrolledGMAWenguncontrolledMulti-attribute decision methodIngenieurwissenschaften und zugeordnete Tätigkeiten9 Komponentensicherheit9.3 Schweißtechnische FertigungsverfahrenMaterialMaterialien und StoffeVerlagsliteraturVolltext-PDF für die Öffentlichkeit verfügbar ("Open Access")Wissenschaftliche Artikel der BAMBundesanstalt für Materialforschung und -prüfung (BAM)https://opus4.kobv.de/opus4-bam/files/35374/Sproesser_GCSM_Procedia_CIRP_2016-02.pdf353762016eng64364840conferenceobjectElsevier B.V.1------Increasing performance and energy efficiency of Gas Metal Arc Welding by a high power tandem processStandard Gas Metal Arc Welding (Standard GMAW) and a high power Tandem GMAW (TGMAW) process are evaluated with respect to energy efficiency. Current, voltage and overall equipment power are measured and energy consumption is determined. The new key performance indicator Electrical Deposition Efficiency is introduced to reflect the energy efficiency of GMAW processes. Additionally, wallplug efficiency of the equipment is determined in order to identify the overall energy consumption. Results show that energy efficiency as well as economic process performance can be significantly increased by application of the TGMAW process. Furthermore findings indicate that wall-plug efficiency of the equipment is independent of power level and material transfer mode. A metal plate of 30 mm thick structural steel is joined by Standard GMAW and TGMAW to demonstrate the total energy savings for a real weld. Electricity consumption is reduced by more than 20 % using the high power TGMAW process.Procedia CIRP10.1016/j.procir.2016.01.1482212-8271urn:nbn:de:kobv:b43-353762http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=Alerting&SrcApp=Alerting&DestApp=WOS&DestLinkType=FullRecord;UT=WOS:00037924320011113th Global Conference on Sustainable Manufacturing - Decoupling Growth from Resource UseBình Dương New City, Vietnam16.09.201518.09.201505.08.2016Creative Commons - Namensnennung-Nicht kommerziell-Keine BearbeitungG. SproesserAndreas PittnerMichael RethmeierenguncontrolledThick metal plate weldingenguncontrolledEnergy efficiencyenguncontrolledTandem Gas Metal Arc WeldingenguncontrolledHigh power weldingIngenieurwissenschaften und zugeordnete Tätigkeiten9 Komponentensicherheit9.3 Schweißtechnische FertigungsverfahrenMaterialMaterialien und StoffeVerlagsliteraturVolltext-PDF für die Öffentlichkeit verfügbar ("Open Access")Bundesanstalt für Materialforschung und -prüfung (BAM)https://opus4.kobv.de/opus4-bam/files/35376/Sproesser_GCSM_2_Procedia_CIRP_2016.pdf412442017eng110conferenceobject0------Electromagnetic porosity Reduction in Laser Beam Welding of Die-Cast Aluminum AlloyThe present paper investigates the electromagnetic porosity reduction in partial penetration laser beam welding of 6 mm aluminum die casting AlSi9MnMg. Applying an electromagnetic field, a significant reduction of the porosity as well as smoothing of the surface of aluminum die casting can be observed. Starting from the reference case without an electromagnetic support, the porosity was reduced by 76 %. Especially big pores can be removed from the weld pool effectively due to their beneficial volume-to-area ratio whereas very small metallurgical pores tend to remain within the weld pool even when higher magnetic flux densities are applied.Lasers in Manufacturing Conference 2017Lasers in Manufacturing Conference 2017Munich, Germany26.06.201729.06.2017André FritzscheKai HilgenbergF. TeichmannH. PriesMichael RethmeierenguncontrolledLaser beam weldingenguncontrolledDie-cast aluminumenguncontrolledPorosity reductionenguncontrolledElectromagnetic influenceIngenieurwissenschaften und zugeordnete Tätigkeiten9 Komponentensicherheit9.3 Schweißtechnische FertigungsverfahrenMaterialVerlagsliteraturVolltext-PDF im Netzwerk der BAM verfügbar ("Closed Access")412462017deu106111conferenceobjectDVS Media GmbHDüsseldorf0------Untersuchungen der Heißrissanfälligkeit laserstrahlgeschweißter Verbindungen austenitischer StähleDie lokalen Dehnungen bzw. Dehngeschwindigkeiten im heißrisskritischen Temperaturintervall sind Funktionen des Temperaturfeldes im Nahbereich des Schmelzbades (Schweißverfahren, Werkstoff), der thermo-mechanischen Kennwerte des Versuchswerkstoffes sowie von außen aufgebrachten Verfor-mungen. Da die lokal vorherrschenden Dehnungen im Nahbereich des Schmelzbades nicht bzw. nur mit sehr aufwendigen Methoden ermittelt werden können, dienen bespielweise die im CTW-Test (Controlled Tensile Weldability) von außen aufgebrachten Dehnungen oder Dehnraten als Kriterium für die Heißriss-empfindlichkeit. In dieser Studie wurde CTW-Test zur Untersuchung der Heißrissresistenz verschiedenen austenitischen Stählen eingesetzt.36. Assistentenseminar Füge- und Schweißtechnik978-3-945023-57-036. Assistentenseminar Füge- und SchweißtechnikBrunswick, Germany05.10.201507.10.2015Nasim BakirAndrey GumenyukMichael RethmeierdeuuncontrolledHeißrissdeuuncontrolledHeißrissresistenzdeuuncontrolledAustenitische StähleenguncontrolledCTW-TestIngenieurwissenschaften und zugeordnete Tätigkeiten9 Komponentensicherheit9.3 Schweißtechnische FertigungsverfahrenMaterialVolltext-PDF im Netzwerk der BAM verfügbar ("Closed Access")Graue Literatur411742017eng18conferenceobject0------Comparative study of hot cracking susceptibility for laser welded joints by means of a self- restraint and an externally loaded hot cracking testsOver the past decade, laser beam welding has significantly evolved and established itself as an efficient tool in the industry. Solidification cracking and the weldability of materials have been highly contentious issues for many years. Today, there are many self and externally loaded tests to investigate the hot cracking resistance of steels. The purpose of this paper is to compare the susceptibility of three stainless steel grades to hot cracking by using an externally loaded hot cracking test (CTW) and a self-restraint test in accordance with SEP-220-3. The repeatability and effectiveness of the results are discussed. The experimental results are widely dispersed, implying a low predictive value for the self-restraint test. On the other hand, the results from the externally loaded test exhibit excellent repeatability and provide a quantitative characterization of the susceptibility of steels to hot cracking.The 5th International Conference on Steels in Cars and TrucksThe 5th International Conference on Steels in Cars and TrucksAmsterdam-Schiphol, Netherlands19.06.201721.06.2017Andrey GumenyukMichael RethmeierNasim BakirenguncontrolledExternally loaded testenguncontrolledHot cracking testenguncontrolledSEP-1220-3enguncontrolledCTW testenguncontrolledSelf-restraint testIngenieurwissenschaften und zugeordnete Tätigkeiten9 Komponentensicherheit9.3 Schweißtechnische FertigungsverfahrenMaterialVerlagsliteraturVolltext-PDF im Netzwerk der BAM verfügbar ("Closed Access")411752017eng17conferenceobject0------Investigation of solidification cracking susceptibility of type 316L stainless steel during laser beam welding using an in-situ observation techniqueLaser welding is a widely established manufacturing process in many industry sectors. Solidification cracking as well as the weldability of materials is still since many years a highly contentious issue, particularly regarding the causes of the hot crack formation. Many of studies have been conducted to determine the critical conditions of occurrence of the solidification cracking. In this study a 2D in-situ observation technique in conjunction with laser diodes as the illuminating source has been employed to measure the arising strain field during the laser beam welding process. For the first time the employed technique enabled the in-situ measurement of the transient strain field at the surface of the workpiece directed to the laser beam in the critical range, where the solidification cracking normally occurs. Thus the critical threshold strain values at high temperatures characterizing transition from crack free to crack concomitant welding process could be deduced.Lasers in Manufacturing Conference 2017Lasers in Manufacturing Conference 2017Munich, Germany26.06.201729.06.2017V. PavlovAndrey GumenyukS. VolvenkoMichael RethmeierNasim BakirenguncontrolledLaser beam WeldingenguncontrolledOptical measurement techniqueenguncontrolledCritical strainenguncontrolledSolidification crackingIngenieurwissenschaften und zugeordnete Tätigkeiten9 Komponentensicherheit9.3 Schweißtechnische FertigungsverfahrenMaterialVerlagsliteraturVolltext-PDF im Netzwerk der BAM verfügbar ("Closed Access")376722016eng76176883conferenceobjectElservier1------Laser metal deposition as repair technology for a gas turbine burner made of Inconel 718Maintenance, repair and overhaul of components are of increasing interest for parts of high complexity and expensive manufacturing costs. In this paper a production process for laser metal deposition is presented, and used to repair a gas turbine burner of Inconel 718. Different parameters for defined track geometries were determined to attain a near net shape deposition with consistent build-up rate for changing wall thicknesses over the manufacturing process. Spot diameter, powder feed rate, welding velocity and laser power were changed as main parameters for a different track size. An optimal overlap rate for a constant layer height was used to calculate the best track size for a fitting layer width similar to the part dimension. Deviations in width and height over the whole build-up process were detected and customized build-up strategies for the 3D sequences were designed. The results show the possibility of a near net shape repair by using different track geometries with laser metal deposition.Physics Procedia10.1016/j.phpro.2016.08.078http://ac.els-cdn.com/S1875389216301857/1-s2.0-S1875389216301857-main.pdf?_tid=ed1d75de-84a2-11e6-af94-00000aab0f6c&acdnat=1474974777_4917d753cb3d316c4b000ba0760778b51875-3892urn:nbn:de:kobv:b43-376723http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=Alerting&SrcApp=Alerting&DestApp=WOS&DestLinkType=FullRecord;UT=WOS:000387459400081LANE - 9 International Conference on Photonic TechnologiesFürth, Germany19.09.201622.09.201613.01.2017Creative Commons - Namensnennung-Nicht kommerziell-Keine BearbeitungT. PetratB. GrafAndrey GumenyukMichael RethmeierenguncontrolledLaser metal depositionenguncontrolledInconel 718enguncontrolledAdditive manufacturingenguncontrolledMaintenanceenguncontrolledRepair and overhaulIngenieurwissenschaften und zugeordnete Tätigkeiten9 Komponentensicherheit9.3 Schweißtechnische FertigungsverfahrenMaterialMaterialien und StoffeVerlagsliteraturVolltext-PDF für die Öffentlichkeit verfügbar ("Open Access")Wissenschaftliche Artikel der BAMBundesanstalt für Materialforschung und -prüfung (BAM)https://opus4.kobv.de/opus4-bam/files/37672/Lane 2016 Physics procedia 83 .pdf